[PATCH v2 1/3] PCI: Move declaration of pci_rescan_remove_lock into public pci.h

[Benjamin Block <bblock@linux.ibm.com>]

So far it is possible to use and call the functions
pci_lock_rescan_remove() and pci_unlock_rescan_remove() from any PCI
code, including modules and architecture code; but the lock variable
`pci_rescan_remove_lock` itself is private to objects residing in
`drivers/pci/` via the header `drivers/pci/pci.h`.

This makes it possible to use the lock - lock it, unlock it - from
anywhere, but it is not possible to use lockdep annotations such as
lockdep_assert_held(), or sparse annotations such as __must_hold() in
modules or architecture code for PCI to make the usage more safe.

Since it is useful for `pci_rescan_remove_lock` to have such
annotations, move the variable declaration into `include/linux/pci.h`.

Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
---
 drivers/pci/pci.h   | 2 --
 drivers/pci/probe.c | 1 +
 include/linux/pci.h | 2 ++
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 13d998fbacce..6d611523420f 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -110,8 +110,6 @@ struct pcie_tlp_log;
 extern const unsigned char pcie_link_speed[];
 extern bool pci_early_dump;
 
-extern struct mutex pci_rescan_remove_lock;
-
 bool pcie_cap_has_lnkctl(const struct pci_dev *dev);
 bool pcie_cap_has_lnkctl2(const struct pci_dev *dev);
 bool pcie_cap_has_rtctl(const struct pci_dev *dev);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index bccc7a4bdd79..e5b12878e972 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -3509,6 +3509,7 @@ EXPORT_SYMBOL_GPL(pci_rescan_bus);
  * routines should always be executed under this mutex.
  */
 DEFINE_MUTEX(pci_rescan_remove_lock);
+EXPORT_SYMBOL_GPL(pci_rescan_remove_lock);
 
 void pci_lock_rescan_remove(void)
 {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 1c270f1d5123..fd7a962a64ef 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -39,6 +39,7 @@
 #include <linux/io.h>
 #include <linux/resource_ext.h>
 #include <linux/msi_api.h>
+#include <linux/mutex.h>
 #include <uapi/linux/pci.h>
 
 #include <linux/pci_ids.h>
@@ -1533,6 +1534,7 @@ void set_pcie_hotplug_bridge(struct pci_dev *pdev);
 
 /* Functions for PCI Hotplug drivers to use */
 unsigned int pci_rescan_bus(struct pci_bus *bus);
+extern struct mutex pci_rescan_remove_lock;
 void pci_lock_rescan_remove(void);
 void pci_unlock_rescan_remove(void);
 
-- 
2.53.0